Spring.



H. w. SANFORD.

SPRING.

APPLICATION FILED MAY I2. I9I4. RENEWED JAN. 15. NH?- 1,217,507. Patented Feb. 27, 1917.

2 SHEETS-SHEET I.

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H. W. SANFORD.

SPRING.

'APPLICATION FILED MAY 12, 1914. RENEWED JAN. I5, I91?- 1,217,507. Patented Feb. 27,1917.

2 SHEETS-SHEET 2.

D h a W 1 l mm mmwunn imhiaiga; k *EMW U I HUGH W. SANFORD, 0F KNOXVILLE, TENNESSEE.

SPRING.

Specification of Letters Patent.

Patented Feb. 2'7, 191 '7.

Application filed Kay 12. 1914. Serial No. 838.004. Renewed January 15, 1917. Serial No. 142,558.

ful Improvement in Springs. of which the following is a specificatimi, reference being had to the accompanying drawing.

My improvement relates particularly to springs wherein air or any other gaseous medimn is used as a resilient element. such resilient element being contained, under more or less (Olfllll'fi-SSlOIl, in a compressible chamber which constitutes a support or resistance for a body or member which is to be protected from shocks. hen the spring is applied to a vehicle.-the vehlcle body 1s to be protected from shocks imparted by the roadway or rails to the wheels of the vehicle. If a) desired; such springs may be associated cooperatively with other springs of any desired type: but the elastic fluid springs of the invention may be used without such association.

Heretofore in the art of spring suspension, air cushioning instrumentalities have been suggested as a substitute for the metallie elliptical or coil springs, but such at-- tempts have, as far as at present known, been unproductive of any substantial or material advantages over the common form of suspension. This is attributed to the fact that in the use of expansible, inflated rubber bulbs there is at all times a variable condition, a quick deterioration of the compressed air container employed. and insuflicient strength. In the relatively movable piston type of cushion or pneumatic spring heretofore suggested, many objections have been found in the adaptation of the device for general service, among which may be mentioned the inability to maintain proper resisting conditions to load and pressures; the necessity of the employment of a relatively movable sliding association of parts, permitting the escape of the contained fluids; and the entrance of foreign substance through the joint. requiring constant attention in the way of lubrication to prevent wear. The present invention is designed to overcome the objections heretofore found to exist in the pneumatic spring art and relates more particularly to a construction wherein a collapsible metallic tube is employed. compressible and expansible in. one

direction only, namely longitudinally or lengthwise and non-ex mnsible transversely. lleretoforc. it has been suggested to employ a convoluted tube of this character capable of longitudinal movement only as distinguished from lateral expansion or contraction. but as far asl am now advised, such suggestions have been substantially unsatis factory, owing to the lack of provision for maintaining the proper air resistance at all times for various loads, in a manner to pr vent destructive collapse or over-compression, which would result in cracking or breakage of the flexible metallic convoluted walls of the container. The present invention may therefore be briefly stated to comprise a structurewherein a convoluted metallic container is employed, non-expansible laterally, but freely collapsible lon 'tudinally, and provided with means w ereby the container may be charged with air under high compression, sufficient to render the device initially operative as a s ring-or buffer, without the danger of disrupting or breaking the flexible convoluted metallic walls under service conditions.

In carrying out the present invention, I employ what is known. as a convoluted tube composed of a flexible sheet metal plate hav ing transverse convolutions or corrugations, each of which is provided with parallel walls and curved connecting walls. Such a structure with its multiplicity of parallel walls is capable of resisting laterally a very high internal pressure, estimated approxr mately one thousand pounds to the square inch. while at the-same time it yields to very moderate or'light pressures lengthwise. I have found. however, that for successful employment of such a tube as a cushioning device. it is necessary to maintain Within the tube a material resistance in the form of compressed air or other gases to an amount or to an extent that there will be present an initial resistance to endwise movement. The compressed charge serves also as a means for preventing collapsing beyond the breaking or disrupting point or the pointof abrasive contact of the convolutions. The invention therefore, consists primarily in the formation of a pneumatic spring wherein the said convoluted metal tubeis employed and providing the same with means forcharging it primarily with ahi hly compressed air or gas in an amount su cient to perform the work desired and to maintain the spring at all times in proper working condition. Further, to add to the interior of the spring, a liquid or other medium,

the effective collapse or compression of the tube, while creating-inan inverse ratio a re sistance so that thecompressed aswiu act as a resisting medium progressively and momentarilythroughout the working movement of the spring, and finally, to associate with. such a structure, proper means for maintaining the spring against accidental overcollapse and against sidewise movement. For the convenience in description, it will be assumed that the spring is applied to an automobile or other road vehicle, the direction of action of the. spring being on an upright line. For other uses, the direction of action may be on lines which are not upright.

In the accompanying drawings,

Figure 1 is a sectional elevation of a structure embodying my improvement;

Fig. 2 is a sectional elevation of the mechanism shown in .Fig. 1, looking toward the right; Fig. Fig. 1;

Fig. 4 is a section on the line, 4-4, of Fig. 1;

Fig. 5 is a sectional elevation of another form of thev mechanism;

Fig-6 is a section on the line, 66, of

3 is a section on the line, 33,-of

' fieferring first to Fig. 1, A is an axle of the vehicle and B is a part of the vehicle body or any sustaining member applied thereto. On the axle, A, is a base plate, suitably secured thereto, and immediately below the part, B, is a top plate, D. Between the base and said .top plate is a sheet metal tube, E, formed into horizontal convolutions, 1, similar to the convolutions of an accordion bellows. Said wall is preferably formed of a plurality of sections each consisting of a single piece of metal which is spun to form annular convolutions, 1, of suf-. ficient width to. allow a considerable range of flexibility of the convolutions, whereby said tube may be compressed by endwise pressure or lengthened by pulling lengthwise of the tube. At its lower end, said tube has an outward-directed flange, 2, fitting closely upon the upper face of the lowerend plate, C, and firmly secured thereto in any suitable manner, as by means of a clampin ring, 3. and screws, 4. The-upper end 0 said tube has a similar flange, 2, bearing against the lower face of the upper end p ate, D, and similarly secured to said plate by means of a clamping ring, 3, and screws,

4. The sheet metal wall is divided transversely into two sections and the meetin ends have outward-directed flan s, 2, whic are clamped between two rings, F, which which will permit "the port, 9. The

Said ringsro'nstitutea guide-member for.

the tube, as described below.

right guide 'a'iini'fiG,---extending downward from and rigid with the upper end plate, I). Said arms are free to slide up and down relative to the plate, C, and the axle; but said arms are'substantially prevented from moving horizontally either transversely to or in the direction of the length of the axle. The latter may be done in various ways, as by means of shoulders, 6, on the plate, C. To limit the upward movement of the upper end plate, stop lugs, 5, 5, are placed on the inner faces of'the guide arms, (i, below the lower end plate. The opposite sides of the tubeand midway between the guide arms, G, are standards, H,- which are of suitable height to bear against the upper end plate when the latter has descended as far as desired. Said standardsserve as stops for limiting the compression of the spring. The ring-form guide member composed of thetwo rings, F, F, extends outward near enough to the guide arms, G, and the standards, H, to be guided by said arms and standards during the compression and extension of the tube. Said ring-form uide'member Serves-as a stay to prevent t e flexible tube from buckling sidewise while the tube is filled with compressed air. While said tube needs such lateral staying, the thin metal of which the wall of said tube is composed must not be allowed to slide against a resisting surface, for that would wear and weaken such wall so as to cause its breakin From the end plate, D, rises a tubular neck, 7, the exterior of which is screw threaded. A cap, 8, is exteriorliy screw threaded and fits around the neck, 7 In the upper end of the cap, 8, is a port, 9. lVithin said cap is an expanding coiled spring, 10, resting upon the neck, 7, andbearing against a ball valve, 11, which rests across upper portion of the extenor of the cap, 8, is screw-threaded and receives the interiorly screw-threaded outer cap, 12. In this manner, the cham ber formed by the two end plates and the tube is provided with a valved inlet. When the cap, 12, has ben removed, a tube leading from an air pump or air compressor may be coupled to the upper portion of the cap, 8, and the air then driven through said tube and'through the port, 9, the cap, 8, and the neck, 7. Thus the chamber formed by the tube, E, and the plates, C and D, is filled with compressedair to a density suitable to the load to be carried. All of theweight of the vehicle bod and its load, may be supported by springs thus formed or these springs and springs of another type may ointly carry the load.

v At each side .of-theaxlc and the end plate, C, is an up The wall of the tube, E, is made of only, such thickness and quality as'will afford .sufiicient strength to confine the air within said chamber, no dependence for supporting the load being placed upon said tube taken by itself. The wall of said tube is made as thin and flexible as is consistent with strength, and the air within the chamber is relied upon for elasticity. The efliciency of the tube as a resilient sustaining member or a are to be varied according to the weight of the vehicle body and according to the desired sensitiveness cf the spring. Such tubes may be made amply strong to contain air under suitable density to support a heavy vehicle body, as, for example, an automobile body, and yet afford such flexibility as will allow the tube to repeatedly shorten and lengthen during the relative up and down movement of the vehicle body.

The tube, E, is not. of sufficient strength a to maintain its upright position against tendency of the vehicle body to shift relatively horizontally. To permit only upright move ment of the vehicle body relative to the axle, the guide arms, G, are placed with their inner faces upright and parallel to each other and near the axle, or any part supported thereby, insuch manner as to substantially prevent horizontal movement,

as above described. It may be said that the structure is such as to permit and limit the movement of the vehicle body substantially to a course which is upright and perpendicular to the axle or parallel to the length of the flexible tube. In ,the form shown in Fig. 1, the guide arms, G, G, operating in conjunction with the lower end plate, constitutemeans for permitting such movement and substantially no other. But when these springs are applied to a road vehicle, the guide arms should not so engage as to limit absolutely to upright movement. count of inertia and momentum of thevehicle, allowance should be made for some horizontal movement relative to the axles;

. but such horizontal movement should be he capacity of the chamber formed by the tube, E, and the end plates for receiving air may be varied by partially filling said sli chamber with liquid, as indicated in Fig. 1; Such liquid is preferably an oil which remains in liquidform under ordinary tem- Oil is preferable to' water. be.- cause the oil rotects the inner faces of the tube and the liase plate and top plate from corrosion. When it is found that the spring peratures.

is more resilient than is desired, the introduction of liquid will reduce the resiliency.

On ac- In the form shown in Fig. 5, the arms, G, G, are omitted and the means used for limiting the vehicle body to a line which is perpendicular to the axle and upright is placed within the tube, E. For this purpose I show a rigid guide tube, 13, rising from the lower plate, C, and a rigid guide tube, 14, extending downward from the upper end plate, D, and telescoping into the tube, 13. This structure may be used by filling the chamber formed by the tube and the top and bottom plates with air only, or said chamber may be filled in part with li uid, preferably oil.

he tube, 13, is shown as having ports, 15, near the base plate. Said ports are amply large to permit a free flow of air or liquid to maintain equilibrium within and around the tubes, 13 and 14. The volume of air to be received by the chamber'formed by the tube, E, and the two end plates may be varied by placing oil within said chamber in the manner already described regarding Fig. 1'.

To adapt the structure to receive oil, as described, the end plates and the tube, E, must be made of material which will not deteriorate in the presence of oil. Metal is suited to this purpose. The oil which regulates the air space in the tube, E, also lubricates the guide tubes, 13 and 14, in Fig. 5.

And in this form, the guide member comend plate.

From the above it will be observed that in use the interior of the convoluted tube will be charged with compressed air in a suflicient amount to initially perform the work, and by the employment of the ball valve, the air charge may be increased or diminished in conformity with the load of work to be done, and further. that by .the addition of the oil or other filler, the full effective action of the compressible tube is permitted. while the charge of compressed gas or air is confined in the upper portion of the tube whereby a fractional compression of the transversely convoluted sheet metal tube leads to a multiple compression of the air within the tube and that fractional compression should be less than one-half of the full length of the tube to preserve the proper relation of the parts and prevent or avoid the related parts of the convolutions from being brought into destructive relation or contact.

1. In a mechanism of the nature de- III 'bers being provide scribed, the combination of two end plates, a sheet-metal tube transversely convoluted and elastic lengthwise and substantially nonelastic transversely and having its ends secured to said end lates,one ofsaid mem- (i with a valved inlet, and means for relatively limiting said plates for movement only parallel to the length of said tube, substantially as described.

-2. A sprin comprising a vessel having rigid end Wa-l and transversely convoluted metallic side walls yieldable only along the lines of the vessels collapse, said vessel containing a charge of initially compressed gas of a density to materially resist initial compression, and a valved charging port in one wall of thevessel.

3. A spring comprising a vessel having rigid end walls and'transversely convoluted ela ic metallic side walls yieldable only alo g the lines of the vessels colla se, said vemel containing a charge ofinitia 1y com-' ressed gas of a'density to materially resist initial compression, a filling body within the vessel, and a valved charging port in one wall of the vessel.

4. In a mechanism of the nature described, the combination of two end plates, an upright sheet-metal tube transversely convo-' luted and elastic lengthwise and substan tially non-elastic transversely and having its ends secured to said end plates, the upper of said end plates being provided with a valved inlet, and means for relatively limiting said lates for upright movement only, substantially as described. I

5. In a mechanism of the nature described, the combination of two end plates, a flexible sheet-metal tube transversely convoluted and having its ends secured to said plates, one of said threemembers bein provided with a valved inlet, a guide mem r on said tube, and means for relatively limiting said guide member and said plates for movement parallel to the length of said tube, substantially as described.

6. In a mechanism of the nature described, the combination of two end plates, an up right flexible sheet-metal tube transversely convoluted and having its ends securedvto said end plates, one of said three members being provided with a valved inlet, a guide member on said tube,-aud means for relatively limiting said guide member and said plates'for upward movement, substantially as described. r

7. In a mechanism of the nature described, the combination of two end plates, a flexible sheet-metal tube transversely convoluted and having its ends secured to said end plates, one of said three members being provided with a valved inlet, means for relatively limiting said lplates for movement parallel to the lengt of said tube, and means applied to said tube between its ends .with a valved: inlet,'and means versely to its length, substantially as described.

8. In a mechanism of the nature described, the combination of two end plates and a tube, one of said three members being pro -vided with a valved inlet, and said tube consisting of two flexible, transversely convoluted sheet-metal sections and a guide mem ber joining said sections, and means for relatively limiting said end plates for movement parallel to the length of said tube, substantially as described.

9. In a mechanism of the nature described, the combination of two end plates, a tube consisting of two flexible, transversel convoluted sheet-metal sections and a gui e member joining said sections, one of said end plates being provided with a valved. inlet, and means for relatively limitmg said end plates for movement parallel to the length 0 said tube, substantially as described.

10. In a mechanism of the nature described, the combination of two end plates, an upright tube consisting of two flexible,

and a gui e member joinin said sections, one of said three members ing tively limiting said plates for u ri ht movement, substantially as described? g 11. In a mechanism of the nature described, the combination of two end plates, an upri ht tube having its ends secured to said en plates and consistin of two flexib le, transversely convoluted sfieet-metabsectlons and a guide member joining said sections, the upper of said end plates being provided with a valved inlet, and means for relatively limiting saidplates for upright movement, substantially as described.

12. A spring comprising a vessel havin rigid end walls and transversely convoluted elastic metallic side walls yieldable only along the line of the vessels collapse, said vessel containing a charge of initially compressed gas of a density to materially resist mitlal compression, a valved charging port in one of the'vessels walls, and means for checking the expansion of the vessel.

'13. A spring comprising a vessel havin rigid end walls and transversely convoluted elastic metallic side walls yieldable only along the line of the vessels collapse, said provided. I

or relapressed gas of a density to materially resist lnitial compression, a valved charging port in one of the vessels walls, and means for limiting the expansion and compression of the vessel.

15. In a mechanism of the nature described, the combination of two end plates, a flexible sheet-metal tube transversely convoluted and having its ends secured to said end plates, one of said three members being provided with a valved inlet, and means for relatively limiting said lates for movement parallel to the length 0 said tube and preventing the flexible tube from buckling sldewise between its ends, substantially as described.

16. In a mechanism of the character described, the combination of two end plates, a flexible sheet-metal tube transversely convoluted and having its ends secured to said end plates, one of said end plates being provided with a valved inlet, and means for relatively limiting said end plates for movement parallel to the length of said tube and preventing the flexible tube from buckling sidewise between its ends, substantially as described.

17. In a mechanism of the nature described, the combination of two end plates, an upright flexible sheet-metal tube transversely convoluted and having its ends secured to said end plates, one of said three members being rovided with a valved inlet, and means. or relatively limiting said plates for upright movement and preventing the flexible tube from buckling sidewise between its ends, substantially as described.

18. In a mechanism of the nature described, the combination of two end plates, a flexible sheet-metal tube transversely convoluted and having its ends secured to said end plates, one of said three members being provided with a valved inlet, and means for relatively limiting said plates for movement parallel to the length of said tube and for limiting the movement of the plates toward and from each other and preventing the flex- I ible tube from bucklin sidewise between its ends, substantially as escribed.

19. In a mechanism of the nature described, the combination of two end plates,

etween its ends,

the flexible tube V vessel containing a charge of initia ly compressed gas of a density to materially resist initial, compression, a valved charging port in one wall of the vessel, and a guide intermediate the ends of the vessel for resisting sidewise movement of the vessel.

22. A spring comprising a vessel having rigid end walls and transversely convoluted elastic metallic side walls yieldable only along the line of the vessels collapse, said vessel containing a charge of initially compressed gas of a density to materially resist initial compression, a valved charging port in one wall of the vessel, a guide intermediate the ends of the vessel for resisting sidewise movement of the vessel, and rigid projecting means on which the guide moves.

23. A spring comprising a vessel having rigid end walls and transversely convoluted elastic metallic side walls yieldable only along the line of the vessels collapse, said vessel containing a charge of initially compressed gas of a density to materially resist initial compression, a valved charging port in the upper wall of the vessel, and an upright rigid member on the lower wall of the vessel arranged to limit the downward movement of the upper wall.

24. A spring comprising a vessel havin rigid end walls and transversely convoluted elastic metallic side walls yieldable only along the .line of the vessels collapse, said vessel containing a charge of initially comressed gas of a densityto materially resist initial compression, a valved charging port inthe upper wall of the vessel, and a depending projection on the upper wall havmg an offset adapted to engage below the lower wall.

25. 'A spring comprising a vessel having rigid end walls and transversely convoluted elastic metallic side walls yieldable only along the line of the vessels collapse, said vessel containing a charge of initially compressed gas of a density to materially resist initial compression, a valved charging ort in the upper wall of the vessel, an upright rigid member on the lower wall of the vessel arranged to limit the downward movement of the upper wall, and a dependin projection on the upper wall having an o set adapted to engage below the lower wall.

26. A spring comprising a vessel having rigid end walls and transversely convoluted elastic metallic side walls yieldable only along the line of the vessels colla se, said vessel containing a charge of initia y! compressed gas of a density to materially resist initial'compression, a filling body within the, vessel, a valved charging port in one wall of the vessel, and means for relatively limiting the movement of said end walls.

27. A spring comprising a vessel havin rigid end walls and transversely convolut elastic metallic side walls yieldable only along the line-of the, vessels collapse, said vessel containing a charge of initially compressed gas of adensity to materially resist initial compression, a filling body within S. E. Homes, CYRUS KEHR. 

